Kinetics of Thermal Oxidation of Titanium Nitride Powder at Different Oxidizing Atmospheres

The oxidation behavior of titanium nitride powder at different oxidizing atmospheres was investigated using thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. Oxidation experiments have been carried out both in isothermal as well as nonisothermal modes. The nonisothermal oxidation result showed that the oxidation rate was affected by temperature, heating rate, and oxygen partial pressure. The isothermal oxidation result showed that the diffusion of oxygen through the oxide product layer to the oxide/titanium nitride interface was the rate-controlling step and the oxidation product became obviously porous at elevated temperature. In view of the oxidation kinetics, Chou model, which quantitatively expresses the oxidation weight increment as a function of time, heating rate, temperature, and oxygen partial pressure, has been employed and gotten a good agreement.